Theoretically, you can definitely improve your grades after losing weight, but it should be noted that you must lose weight healthily in order to maintain a good physique, otherwise your body will be overwhelmed and your exam results will be affected. I don't advise you to implement a weight loss plan when the exam is near, because it is very difficult and risky to concentrate on adjusting your physical condition, paying attention to rest and paying attention to diet, which is also the most important thing in the exam.